This was our experience with Dr. Langston: Very long story short, he failed to do simple tests that would have led to a diagnosis of a dangerous condition that put my daughter in a life-threatening situation. At the time, she was two months old and still had not regained her birth weight (yes, at 2 months!) He had us come in for weekly weight checks, advising us to supplement with formula to get her to gain more. This didn't work because it turned out my daughter was fighting an infection that, in retrospect, I think was going on undetected for at least six weeks. Dr. Langston completely missed it. He never even considered her to have a basic "failure to thrive" diagnosis, which was certainly the very least of her situation.
Within 24 hours of switching to a great new pediatrician (Julia Getzelman - www.getzwell.com), simple blood and urine tests were done and we were told to immediately go to the emergency room based on some frightening results. My daughter was in immediate danger of seizure and/or heart arrhythmia. We were moved to the Pediatric ICU at CPMC for a few days and then to their pediatrics floor. We were in the hospital getting my daughter stabilized and treated from the fallout for over a week.
It seems to me that there's nothing too concerning for Dr. Langston. No one wants a doctor that's an alarmist over every tiny thing, but in our case he was the extreme opposite. Long after he should have taken action, he was still stalling (for what, I don't know). It seems his approach is to "wait and see" long beyond the period he should. His standard response is a pat on the back and reassurance that it'll all be fine. Great if everything really is fine -- but dangerous if it's not. I've also heard about other people who have left for similar reasons.